The first National Weather Service health alert for red tide was issued in Florida this week: According to an online bulletin released by the weather service Tuesday afternoon, "red tide has been identified along portions of the southwest Florida coast."

Red tide is the common name for a harmful form of microscopic algae that forms in the ocean.

The algae produce a toxin that can be released into the air by breaking waves and then blown onshore; the toxin can cause acute respiratory problems for people, especially those suffering from asthma, emphysema or other chronic respiratory disorders, the weather service warns.

"Over the past few days, reports of respiratory irritation have been received from Sarasota and Charlotte counties," the weather service report notes. "Reports of dead fish have been received from Charlotte County."

The Tampa Bay weather forecast office is the first to issue a red tide alert for harmful algal blooms, as part of a new "beach hazard statement" system recently instituted by the weather service.

The warning is in effect at least through Thursday evening, according to the weather service.